computer science, math, programming and other stuff
a blog by Christopher Swenson

Why Hiring is Impossible

For the purposes of this article, I am speaking of the "tech" industry in general (for companies of all sizes), especially for programmers, as that is where I have experience.

Hiring people fairly is impossible, and therefore, meritocracy is a myth. (Here, meritocracy means the idea that you can identify and reward the "best" people.)


There is one simple reason for that.

(I am a mathematician, so bear with me here.)

First, the hiring process is binary. At the end of the process, you either hire someone or you don't, assigning them a value of 0 or 1.

This means you have assigned a 1-dimensional number to each candidate. (Which makes sense, because mathematically you can only unambiguously, or fairly, you might say, compare 1-dimensional numbers.)

This means that, no matter the set of people that you have, you fundamentally have to compare them. That is, you need to boil them down to a single number — 0 or 1 in the hiring sense, or to a more general real number if you want more granularity, like a number 1 to 5 or -1 to 1. (Mathematically, this is similar to defining a total order or metric space.)

The problem is: people are not a single number.

The fundamental theorem of people is: you cannot boil a person down to a single number.

Say that person A is a more reliable Python programmer than person B, but person B is more creative. And Person C is in between A and B in programming ability, but learns quickly. And Person D is a weak programmer, but can understand and destroy any technical problem. And Person E is a slow coder, but can be trusted to document and test their code thoroughly. And Person F tackles problems in an entirely different way.

Who is "better"?

The answer: no one can be objectively better than the others, in general. Ultimately, who you hire should depend heavily on many other questions that are hard to quantify, and don't even entirely depend on the candidate: who is on your team now? Which people will work best with them, and with people you might hire in the future? Which person's strengths and weaknesses are complement the team as a whole? None of these questions are truly objective or depend solely on the intrinsic attributes of the candidate.

The job of the hiring manager is to boil down all of these parts of the people into a single number: 0 (don't hire) or 1 (hire). It is impossible to do this fairly and objectively for everyone.

That this is unfair and subjective is obvious to anyone who has been through the hiring gauntlet at most tech companies. They use a variety of methods to try to measure candidates, such as takeaway programming problems, pair programming exercises, whiteboard coding, brain teasers and puzzles, favoring certain degrees, requiring years of experience, or looking at open source work. Some people do well with one method or another, and some don't. You can't fairly say that because someone is worse at a whiteboard under high pressure that they will make a worse employee, or that someone being excellent at a take-home problem will work well with the existing team. The person at the whiteboard might simply be having an off day, they might not deal well being under the microscope of a high-pressure whiteboard interview, or even the person conducting the interview may not be able to guide them through the interview fairly. Likewise, acing a take-home exam demonstrates some ability to solve problems in a certain scenario, but does little to show how well they communicate or work with others.

It all comes down to: all hiring processes are doomed to be unfair. You should accept that, and come to terms with it. Then, you should examine your hiring processes, make them as fair as possible, and know exactly how they are unfair. Only by understanding your own strengths and weaknesses as a company, hiring manager, or interviewer will you even come close to being able to hire people and set them up for success.